1970 FJ40 carb? trouble

[espensen]

Hm that doesn't help much. But now I can turn the idle mix screw to the bottom while it idles just fine, could that be a sign for something?

 

[thebigredrocker]

What a about a bigger main jet?

If you run out of things to try, you could remove the points and install Pertronix.

 

[Vintij74]

Drilling will work if you are careful.

Check Mikuni jet archives, I believe the thread pitch matches Toyota jets. @65swb45 rebuilt my early 2 barrel with excellent results. Change out fuel filter and run a 1/2 tank of 91 octane with can of Seafoam. Best of luck with your nice cruiser!

 

[ryanwk628]

I had the same problem with my 1970. I thought it was the carb, dizzy or vac leaks. I also thought it couldnt be my fuel pump because it was working well enough for my stationary tests. However it turned out to be a bad fuel pump diaphragm that couldnt keep up under load and once I got a new one from City Racer LLC my problem was solved.

 

[espensen]

Hello!
A last update I hope! I sent the vehicle to a carb guy for a check. He measured the exhaust and found the engine was getting too rich mix. He adjusted the idle until the mix was good. After driving it for a while now it is only sometimes a slightly hesitation when I floor it. So thats good.
So thank you everyone for your suggestions.

 

[MIKKELSEN]

Uffda! It is not likely to be too much fuel, but rather much more likely to be too little fuel. Does it spit back through the carb or backfire when it dies? YES. Does the accelerator pump nozzle squirt fuel when you open the throttle? YES. Is there any fuel dripping out of the primary main nozzle at idle? YES. What is the manifold vacuum at idle?



Everything you describe sounds like stuff my carb is doing what is your suggestion?

 

[MIKKELSEN]

Uffda! It is not likely to be too much fuel, but rather much more likely to be too little fuel. Does it spit back through the carb or backfire when it dies? Does the accelerator pump nozzle squirt fuel when you open the throttle? Are there any vacuum leaks? Is there any fuel dripping out of the primary main nozzle at idle? What is the manifold vacuum at idle?

The soft copper tube is bad practice for fuel line. They crack and leak due to vibration. Use steel tube.

Copper is really dangerous to use as brake lines for the same reason and for the reason that it won't hold up to high pressure.

Hey Pinhead. What you describe is what my freshly rebuilt carb is doing. What do you think is up with it?